1. Field of the Invention
The present invention relates to a surface treating method for treating a surface of a substrate and a film depositing method for depositing a film on the substrate.
2. Description of the Related Art
In recent years, a wide range of materials from inorganic materials to organic materials are used for a semiconductor device. The characteristics of the organic materials (of which inorganic materials do not have) help to optimize the properties of the semiconductor device and the manufacturing process of the semiconductor device.
One of the organic materials is polyimide. Polyimide has a high insulating property. Therefore, a polyimide film obtained by depositing polyimide on a surface of a substrate can be used as an insulating film, and as an insulating film of a semiconductor device.
As a method for depositing the polyimide film, a film deposition method is known, where vapor deposition polymerization is performed by using, for example, pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) as raw material monomers. Vapor deposition polymerization is a method that causes thermal polymerization of pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) (being used as raw material monomers) on a surface of a substrate (see, for example, Japanese Patent No. 4283910). Japanese Patent No. 4283910 discloses a film deposition method where a polyimide film is deposited by vaporizing PMDA and ODA monomers in a vaporizer, feeding each of the vaporized gases to a vapor deposition polymerization chamber, and causing vapor deposition polymerization on a substrate.
However, the film deposition apparatus which deposits a polyimide film by supplying the above-described PMDA gas and ODA gas to the substrate has the following problems.
In order to improve the adhesive property of the polyimide film deposited on the substrate, surface treating is to be performed with an adhesion accelerating agent before depositing the polyimide film. The surface treatment using the adhesion accelerating agent may be performed by treating the surface of the substrate with an adhesion accelerating agent such as a silane coupling agent. Further, in order to cause hydrolysis of the silane coupling agent when treating the substrate surface with the silane coupling agent, water vapor is to be applied to the substrate together with the silane coupling agent.
However, in a case where water vapor that is fed during the surface treatment is remaining, a source gas would react to the water vapor and change the property of a film being deposited on the surface treated substrate. Thus, the film may not be satisfactorily deposited. Further, particles may be generated due to polymerization between the silane coupling agent contained in the adhesion accelerating agent and the water vapor.
Further, in order to perform surface treatment by supplying the silane coupling agent and the water vapor, the surface of the substrate is to be terminated with a hydroxyl group. Therefore, in a case where a Si wafer is used as the substrate, the surface of the substrate is to be terminated with a hydroxyl group after performing dilute hydrofluoric (DHF) cleaning, terminating the surface of the substrate with hydrogen, and cleaning the surface of the substrate by ammonia peroxide (standard clean, (SC) 1) cleaning. This results in a problem of requiring many steps for adjusting the terminating state of the substrate surface.
The aforementioned problem no only applies to a case of depositing a polyimide film on a substrate by feeding a source gas formed of PMDA gas or a source gas formed of ODA gas, but also to a case of depositing various films by feeding various source gases on a substrate.